First-principles calculations on the mechanical, electronic, magnetic and optical properties of two-dimensional Janus Cr$_2$TeX (X= P, As, Sb) monolayers

TL;DR

This study uses first-principles calculations to explore the mechanical, electronic, magnetic, and optical properties of Janus Cr$_2$TeX monolayers, revealing their potential for future nanodevice applications due to their ferromagnetism and half-metallicity.

Contribution

It provides a systematic theoretical investigation of Janus Cr$_2$TeX monolayers, highlighting their ferromagnetic half-metallic nature and stability under strain, which was not previously reported.

Findings

All three monolayers are intrinsic ferromagnetic half-metals.

Curie temperatures are estimated to be above room temperature.

Cr$_2$TeP$ has a higher optical absorption in the visible region.

Abstract

Janus materials possess extraordinary physical, chemical, and mechanical properties caused by symmetry breaking. Here, the mechanic properties, electronic structure, magnetic properties, and optical properties of Janus Cr$_2$TeX (X= P, As, Sb) monolayers are systematically investigated by the density functional theory. Janus Cr$_2$TeP, Cr$_2$TeAs, and Cr$_2$TeSb are intrinsic ferromagnetic (FM) half-metals with wide spin gaps and half-metallic gaps. Monte Carlo simulations based on the Heisenberg model estimate the Curie temperature (\emph{T}$_c$) of these monolayers are about 583, 608, and 597 K, respectively. Additionally, it is found that Cr$_2$TeX (X= P, As, Sb) monolayers still exhibit FM half-metallic properties under biaxial strain from -6% to 6%. At last, the Cr$_2$TeP monolayer has a higher absorption coefficient than the Cr$_2$TeAs and Cr$_2$TeSb monolayers in the visible region. The results predict that Janus Cr$_2$TeX (X= P, As, Sb) monolayers with novel properties have good potential for applications in future nanodevices.